According to the Library of Congress, 18,000 of the notes were printed before the Treasury Department decided to change the design.

Only three of the notes remain in private collections today, and each one is valued at over $1 million. Another of the bill sold in Dallas four years ago for $3.29 million.

Because the United States never demonetizes its currency, the bill is technically still legal tender, says Treglia. You could take it to the bank to exchange it for $1,000 in cash. But just because you can, doesn’t mean you should, he said.